The objectives of this proposed investigation are two-fold. First, to observe the effects of commonly used drugs on labeled Dexamethasone clearance. The drugs to be investigated include theophylline, ephedrine and disodium cromoglycate. The second objective of the proposed investigation is to compare Dexamethasone kinetics in asthmatics requiring long-term daily corticosteroid therapy to those requiring alternate day medication. The investigation will include the analysis of Dexamethasone kinetics using a two compartment model as well as measurement of total and fractional urinary radioactivity. In addition, measurement of pulmonary function tests, clinical evaluation and concentration of urinary 6-hydroxy cortisol will be performed.